37 US Senators have urged President Obama to sign an executive order banning federal contractors from discriminating against LGBT employees.

In a letter released by the Washington Post on Thursday, the group of 37 senators, led by Senator Jeff Merkley of Oregon called on President Obama to implement the Employment Non-Discrimination Act (ENDA), which would end such discrimination.

The legislation has been stuck in the US Congress, but it could be implemented via an executive order.

“Issuing an executive order that includes sexual orientation and gender identity is a critical step that you can take today toward ending discrimination in the workplace,” the senators said.

“By expanding protections for LGBT employees of federal contractors, you would be helping to ensure that all Americans get an equal opportunity to succeed and that federal taxpayer dollars are used to support companies with the best employment practices.”

Some LGBT campaigners have accused the White House of dragging its feet on the issue.

No Republicans have signed the letter, notable Democrats that have added their names include Tammy Baldwin, the first openly gay member of the US Senate.

Since last April, the White House has repeatedly said it won’t issue such a directive at this time and prefers a legislative approach to protecting LGBT workers against discrimination rather than using an executive order.

Current federal law bans discrimination on the basis of sex, race and national origin but do not stop an employer from firing or refusing to hire a worker based on sexual orientation.

21 states and the District of Columbia ban employment discrimination based on sexual orientation.